Polyimides

ABSTRACT

POLYAMIDES ARE OBTAINED FROM THE REACTION OF AN OLIGIMERIC BIS-IMIDE AND A SULFIDE SUCH AS HYDROGEN SULFIDE, AN ORGANIC DITHIOL, OR MIXTURES OF SUCH SULFIDES IN THE PRESENCE OF A PORTTON DONOR. THESE POLYMERIC COMPOSITIONS HAVE USES IN PACKAGING AND MOLDING APPLICATIONS, AS INSULATING MATERIALS, AND AS MEMBRANES FOR THE SEPARATION OF GASES.

United States Patent Oflice 3,766,138

Patented Oct. 16, 1973 II is reacted with hydrogen sulfide, in the presence of a 3,766,138 proton donor (i.e. in the presence of an acidic hydrogen POLYIMIDES ion), the reaction between the bis-maleimide and hydro- James Criveuo, Mechanicvme assign to gen sulfide proceeds smoothly to give soluble, fusible General Electric Company 5 polymers. No Drawmg' 33 163410 The term proton (H+) donor is intended to mean Us. CL CZ 11 Claims any compound, whether organic or inorganic, capable of ionizing to give a proton and includes, for instance, inorganic acids (e.g., HCl, HClO H PO H 80 etc.);

ABSTRACT OF THE DISCLOSURE 1 organic carboxylic acids (e.g., formic acid, acetic acid,

Polyamides are obtained from the reaction of an olipropionic acid, benzoic acid, isobutyric acid, tri fluoroacegimeric bis-imide and a sulfide such as hydrogen sultic acid, maleic acid, etc.); organic compounds containfid an Organic dithiol, or mixtures of such sulfides in ing weakly acidic hydrogen atoms in the form of nuclearthe Presence Of a proton down These polymeric ly bonded hydroxyl groups (e.g., phenol and substituted positions have uses in packaging and molding applica- 15 tions, as insulating materials, and as membranes for the separation of gases.

phenols, including mesitol, cresol, xylenol, hydroquinone, etc.); acidic inorganic and organic salts (e.g., ammonium chloride, ammonium sulfide, trialkyl ammonium salts, for instance, tributyl ammonium chloride, etc.); etc.

The amount of the proton donor can be varied widely. Generally, it is present in an amount sufficient to suppress This invention is concerned with polyimide compositions. More particularly, the invention relates to a polymer composed of recurring structural units of the forthe competing anionic polymerization leading to the g l mula stage. Based on the weight of the bis-maleimide, the

0 o 0 rrzo- 011, 112o-ti\ /ii-0H, N--RN NR-N l 0 0 --NHRNHCC- o0-s-(R's),

H H ll H H H l5 H O O n where the Rs can be the same or different divalent orproton donor may range from 0.5 to 10%, by weight, or ganic radicals selected from the class consisting of dimore. If desired, the acidic proton donor can be present valent hydrocarbon radicals of from 1 to 40 carbon atoms in larger amounts so as also to act as the reaction mediand divalent groups consisting of two aryl residues atum, for instance, in connection with the use of materials tached to each other through the medium of a member such as acetic acid, cresol, etc. selected from the class consisting of an alkylene radical The bis-imides of Formula II may be prepared by first of from 1 to 10 carbon atoms forming the bis-imide l -s-, so,, E and -0- (1V) 0 0 HC- ii-(1H R can be any divalent organic radical, n is a whole number in excess of 1, for instance, 2 to 10,000 or more, and xisOor 1. H -o o- H The invention also includes methods for making polya meric compositions of Formula I by effecting reaction, in the presence of a proton donor, between a bis-maleimide of the gfineral formula by efiectmg reaction between a diamino compound of the formula (II) 0 0 (V) NH R-NH HC- Hi-CH Ego-l7 l-CH and maleic anhydride where R has the meaning given ll above. In practice, the compositions of Formula IV may H -o Cg-NHRNH%C C- H be obtained by effecting reaction ina well-known fashion between 2 mols of maleic anhydride and the diamino compound of Formula V.

The bis-irnides of the General Formula IV can be varied widely depending on the kinds of organic radicals which are present therein. Among the divalent groupings with a sulfide (hereinafter so generically identified) selected from the class consisting of H 5 and organic dithiols of the general formula (III) HS-R'-SH which R may broadly and more specifically represent are, advantageously in the presence of a solvent for one or p for instance, divalent saturated alkylene radicals of up both of the reactants and for the reaction product, where to 40 carbon atoms P mStanFe, 1 to 10 ethylene, R and have the meanings given above The above propylene, butylene, isopropyhdene, hexylene, cyclohexidentified compositions of Formula I can also be made ylene the divalent radical of diethyhrne oxide of by forming an aqueous emulsion of the bis-imide in the formula 2 2- 'y which state the bis-imide is reacted with the sulfide. including variofls isomers thereof (e-g-, m-phenylene,

When bis-maleirnides of Formula II are reacted, with p-p y p. p'- p y In,m-b1phenylene, dlchlohydrogen sulfide, for example, one obtains a gelled, subrophenylene, biphenylene methylene of the formula stantially infusible and insoluble mass. This resulting product has little if any commercial utility. Unexpectedly, 0 CH I have discovered that when a bis-maleimide of Formula biphenylene oxide, biphenylene sulfone', biphenylene sulfide, keto biphenylene of the formula etc. Obviously, the arylene radicals may be attached to nitrogens through the ortho, meta or para positions.

Typical examples of the bis-imides of Formula IV are, for instance,

N,N'-ethylene-bis-maleimide, N,N'-m-phenylene-bis-maleimide, N,N-p-phenylene-bis-maleimide, N,N-hexamethylene-bis-maleimide, N,N'-p,p-diphenylmethane-bis-malelmide (hereinafter referred to as BMI), N ,N-p, p'-diphenylether-bismaleimide, N,N'-p,p'-diphenylthioether-bis-maleimide, N,N-p,p'-diphenylsulfone-bis-maleimide, N,N'-4,4-dicyclohexylmethane-bis-maleimide, N,N-m-xylylene-bis-maleimide, N,N'-p,p-benzophenone-bis-maleimide, N,N'-(3,3-dichloro-p,p'-biphenylene) bis-maleimide, N,N'-p,p-diphenylmethane-bis-(methylmaleimide), N,N'-p,p-diphenylmethane-bis-(dimethylmaleimide) which can be made from pyrocinchonic anhydride and 4,4'-diaminodiphenyl methane, etc. Halogenated derivatives of such bis-imides where halogen is on an aryl nucleus can also be employed without departing from the scope of the invention, e.g., N,N'-(3,3-dichloro-4,4'-biphenyloxy) bis maleimide, N,N'-(3,3'-dibromo-4,4-diphenylmethane)-bis-maleimide, etc. Mixtures of the bisimides can also be used if desired.

The above bis-imides of Formula IV can be prepared by reacting two moles of maleic anhydride (or other methyl-substituted maleic anhydride required for making the bis-imides of Formula IV) with one mole of a suitable diamino compound. Mixtures of anhydrides can be used if desired. Typical of the diamino compounds which may be employed for making the bis-irnides of Formula IV may be mentioned, for instance,

meta-phenylene diamine;

para-phenylene diamine; 4,4'-diamino3,5,3,5'-tetramethyldiphenyl methane, 4,4'-diamino-diphenyl propane; 4,4'-diamino-diphenyl methane; 4,4'-diamino-diphenyl sulfide; 4,4'-diamino-diphenyl sulfone; 3,3'-diamino-diphenyl sulfone; 4,4'-diamino-diphenyl ether; 4,4-diamino-3,5,3',5'-tetrachloro-diphenyl methane, 1,5-diamino-naphthalene; 3,3-dimethyl-4,4'-diamino-biphenyl; 3,3'-dimethoxy benzidine; 2,4-bis-(beta-amino-t-butyl) toluene; bis-(para-beta-amino-t-butylphenyl) ether; para-bis-(2-methyl-4-amino-pentyl) benzene; para-bis-( 1,l-dimethyl-5-amino-pentyl) benzene; a,a-diamino-m-xylylene; a,a'-diamino-p-xylylene;

bis (4-amino-cyclohexyl) methane; hexamethylene diamine;

heptamethylene diamine;

octamethylene diamine;

nonamethylene diamine;

decamethylene diamine; 3-methylheptamethylene diamine; 4,gdimethylheptamethylene diamine;

4 2,11-diamino-dodecane; 1,2-bis-(3-amino-propoxy) ethane; 2,2-dimethyl propylene diamine; 3-methoxy-hexamethylene diamine; 2,5-dimethylhexamethylene diamine; 2,S-dimethylheptamethylene diamine; 5-methyln0namethylene diamine; 1,4-diamino-cyclohexane; 1,12-diamino-octadecane; and mixtures threeof.

Having obtained the bisimide of Formula IV, the hismaleimides of Formula II are then prepared by effecting reaction between the bisimide of Formula IV with a diamino compound of Formula V, many examples of which have been given above, under such conditions that the oligomer of Formula II is obtained. This is advantageously accomplished by effecting contact between one mol of the organic diamine of Formula V and about two mols of the bisimide of Formula IV in the presence of an effective amount of an acidic catalyst including organic carboxylic acids, particularly mineral acids as well as specific acidic materials such as fluoroboric acid. Other acids which may be employed for the purpose are propionic acid, chloroacetic acid, trichloroacetic acid, perchloric acid, hydrobromic acid, oxalic acid, etc. The first catalyst often can be employed as a solvent for the mixture of the organic diamine and the bisimide reactant of Formula IV.

Generally the bisimide of Formula IV and the organic diamine of Formula V are contacted in the presence of the acid catalyst while maintaining the temperature in the range of between about 25 C. to 175 C. Effective results can be achieved in the absence of organic solvents particularly where the acid catalyst is utilized as the solvent. If desired a suitable organic solvent such as benzonitrile, acetonitrile, dimethylformamide, N-methyl pyrrolidone, etc. can be employed to facilitate contact between the reactants and to recover the final product. The proportion of the organic diamine to the bisimide of Formula IV to form the oligomer of Formula II should vary within fairly limited ranges. For optimum results, one employs a molar ratio of 2 mols of the bisimide of Formula IV per mol of the organic diamine of Formula V. A slight molar excess of the bisimide of Formula IV (about a 0.001 mol excess) can be employed if desired to effect completion of the reaction.

At temperatures between the range of 25 C. to C., the reaction time can be as long as 2 to 3 hours or more. In some instances depending on such factors as the particular reactants employed, the acid catalyst, etc., effective results can be achieved at ambient temperatures or under reflux conditions where the acid catalyst is employed in amounts sufficient to serve additionally as a solvent for the reactants. In particular instances, effective results can be achieved with as little as 0.1%, by weight, of the acid catalyst based on the total weight of the reaction mixture.

Recovery of the oligomer of Formula II can be achieved by standard methods such as precipitation with an appropriate liquid such as water, acetone, or methanol, etc. The particular organic diamines which may be employed are the same ones which can be used in making the bisimide of Formula IV.

The following examples describe the preparation of selected oligomers of Formula II prepared in accordance with the procedures outlined above.

EXAMPLE 1 This example illustrates the preparation of an oligomer having the formula N- CH; N I (Ii -orr- N Q @xg dried to give 18.1 grams of the desired oligomer (99.2%

yield) having a softening point of about 154 C. The identity of this product was established by infrared and NMR spectra. Elemental analyses as shown below also established the fact that the desired product was obtained.

Found (percent): C, 71.7; H, 4.79; N, 8.70. Calculated (percent) C, 72.2; H, 4.63; N, 9.18.

EXAMPLE 2 This example shows a preparation of an oligomer having the formula Emplaying a reaction vessel and procedure similarly as in Example 1, 35.8 grams (0.1 mol) BMI, 10.0 grams (0.05

mol) 4,4-diaminodiphenyl ether, 100 ml. distilled cresol and 1 ml. acetic acid were mixed together and heated at 120 C. under a nitrogen atmosphere for 15 hours. The oligomer was precipitated by adding methanol, washed, filtered and extracted with methanol and finally dried in vacuum to give 39.6 grams of a product of Formula VII having a softening point within the range of l90210 C. The identity of the oligomer of Formula VII was established by the following elemental analyses. Found (percent): C, 70.1; H, 4.5; N, 9.2. Calculated (percent): C 71.84; H, 3.97; N, 9.20.

EXAMPLE 3 In this example, an oligomer of the formula (VIII) was prepared as follows. Employing the same procedures as described in the aforegoing two examples, 12.4 grams (0.05 mol) 4,4'-diaminodiphenyl sulfone, 35.8 grams (0.10 mol) BMI, 100 ml. cresol and 1 ml. glacial acetic acid were mixed together and the reaction mixture heated at 100-110 C. for about 15 hours. At the end of this time, the oligomer was precipitated with methanol, filtered, washed and extracted overnight with ethanol and dried in vacuum to give about an 80% yield of the aboveidentified oligomer of Formula VIII, having a softening point within the range of 155 C.-173 C. The identity of the oligomer was established by the following elemental analyses. Found (percent): C, 69.1; H, 4.1; N. 7.5. Calculated (percent): C, 67.2; H, 4.1: N. 8.7.

More complete directions for preparing other compositions within the scope of Formula II may be found disclosed in my copending application, Ser. No. 23,491, filed Mar. 27, 1970 and assigned to the same assignee as the present invention. This latter application is concerned primarily with making polymers from bis-imides and polyamines, but some of the procedures described in this patent application are applicable to making the oligomers of the instant invention.

The organic dithiols which can be employed are not critical and can be any one of those which have at least two free thiol (-SH) groups present. Generally the organic dithiol should be free of primary or secondary aliphatic amine groups. Among such organic dithiols which can be employed, including dithiols containing a divalent alkylene radical of from 2 to 20 carbon atoms, are, for instance,

1,2-ethanedithiol 1,3-propanedithiol 2-methyl-2,4-pentanedithio1 1,6-octanedithiol 1,6-hexanedithiol 1,10-decanedithiol 1,18-octadecanedithiol 1,20-eicosanedithiol 1,3 8-octatriocontanedithiol 3,6-dioxa-1,8-octanedithiol l,4-di(3-mercaptophenyl)butane 2-mercaptoethyl-3- (Z-mercaptoethyl)phenylsulfide dithioresorcinol dithioresorcinol 3-(2-mercaptoethyl -6- (mercaptomethyl pyridine 2,5-dimercapto-1,3,4-thiadiazole l,2,4-thiadiazole-3,5-dithiol ethylene glycol bis-(mercaptoacetate) beta-mercaptoethyl ether Z-mercaptoethyl sulfide 3,4-dimercaptotoluene 2,3-dimercaptopropanol CH3 CH3 HSCH CH2SH The reaction of the sulfide and the bis-imide (or mixtures of bis-imides) of Formula II may be carried out by merely mixing the ingredients together at room temperature and permitting the reaction to proceed whereby the exothermic heat of reaction may increase the temperature up to 40 to 50 C. Heating in the range of about 50 to 200 C. .for a length of time required to obtain the desired polymer can also be used if it is desired to accelerate the reaction. Generally, temperatures on the order of about 50 to 150 C. are adequate for the purpose.

Ordinarily, it is desirable to effect reaction between the bis-imide and the sulfide in the presence of a solvent which is inert to the reactants and the reaction product and yet is a solvent for at least one of the reactants and certainly for the reaction product. Typical of such solvents which may be employed for the purpose are benzene, xylene, chlorobenzene, trichlorobenzene, cresol (including mixtures of cresols), N-methyl-Z-pyrrolidone, dimethylformamide, etc. The choice of solvent is not critical and any one which satisfies the above conditions of inertness and solvation can be advantageously used. On a weight basis, the solvent may comprise from 1 to 50 or more parts of the solvent per part of the reactant or reactants. Generally, when using hydrogen sulfide, it is advisable to dis solve the bis-imide in a suitable solvent and then pass hydrogen sulfide gas into the solution.

Although the reaction betwen the bis-imide and sulfide tion. Among such organic peroxides may be mentioned, proceeds fairly well under many conditions, I have found dicumyl peroxide, benzoyl peroxide, tertiary butyl perthat the incorporation of certain catalyst materials markbenzoate, tertiary butyl hydroperoxide, azo-bisisobutyroedly improves the rate of reaction and the time in which nitrile, etc. Generally the amount of cure accelerator optimum yields are obtained. Among such catalysts which employed for the purpose can range from about 0.01 may be mentioned are, for instance, tertiary amines, for to as high as 5 percent or more, by weight, based on the example, triethyl amine, tri-n-butylamine, etc. Other cataweight of the polymer. lysts which have been .found useful particularly when em- In addition to the foregoing mixture of ingredients, it ploying a two-phase emulsion system in which the monois possible to blend the polymer of Formula I with other mer is dissolved in a solvent, such as cresol, and the cata- 10 polymers and resins in amounts ranging from about 1 lyst is dissolved in water and the total mixture emulsified to 75 percent or more, by weight, of the polymer based with emulsifying agents such as carboxy methyl cellulose on the total weight of the polymer of Formula I and include sodium carbonate, potassium carbonate, sodium the other polymeric ingredient. Included among such bicarbonate, etc. Generally, when polar solvents such as polymers may be mentioned polyolefins (e.g., polyethyldimethylformamide, N-methyl-Z-pyrrolidone, dimethyl ene, polypropylene, etc.) polystyrene, polyphenylene sulfoxide, etc., are employed, catalysts are normally not oxides such as shown in U.S. 3,306,875, epoxy resins needed to effect the desired reaction. such as shown in U.S. 2,840,540, polycarbonate resins The amount of catalysts used can vary widely. Gensuch as shown in U.S. 3,028,365, silicone resins such as erally no more should be employed than is necessary to shown in U.S. 2,258,2l8222, phenolaldehyde resins, effect optimum completion of the reaction. Ordinarily, polyamide resins such as shown in U.S. 3,179,633-634, no more than 0.01%, by weight, of the catalyst, based on polyarylene polyethers such as shown in U.S. 3,332,909,

the weight of the bis-imide is required, and usually etc., many of which are well-known and well-documented amounts of the order of 0.000l% to 0.001%, by weight, in the art. of the catalyst, based on the weight of the bis-imide, are In order that those skilled in the art may better undersufficient. stand how the present invention may be practiced, and The amount of sulfide used should be at least equal in how the polymers of Formula I can be prepared, the molar concentration to the mols of bis-imide employed. following examples are given by way of illustration and Thus, for higher molecular weight products, there should not by way of limitation. be employed about 1 mol or even slightly more than 1 The intrinsic viscosities recited in the following exmol (to insure completion of the reaction) of the sulfide amples were measured in dimethylformamide at 25 C. per mol of the bis-imide. The rate of passage of H S is EXAMPLE 4 not critical and can be varied widely when the latter is used. Generally, from 1 to 10 mols, per mol bis-imide is In this example, 5 grams of the oligomer of Example 1 satisfactory. (Formula VI) were dissolved in 50 ml. cresol together After obtaining the polymer which may require rewith about 2 drops of tetramethylethylenediamine as a action for times ranging from about 5 minutes to 2 to 3 catalyst. Hydrogen sulfide gas was passed through the hours or more, the solution of the polymer is treated cresol solution of the oligomer for about 1 hour at an with a non-solvent such as water or a lower alkanol, such even rate of approximately 1 liter of hydrogen sulfide as methanol, to precipitate the polymer and the polymer during this period while the temperature of the solution can then be isolated in well-known manner and used for was maintained at around 58 C. At the end of this paswhatever purpose intended. In addition to being soluble Sage of hydrogen sulfide, a highly viscous reaction mixin many solvents referred to above, particularly the creture was obtained which was then precipitated with sols, these polymers are usually soluble in other solvents acidified methanol. The solid polymer thus resulting was such as dimethylformamide, dimethylsulfoxide, etc. The retnoved y filtration, extraded With ot methanol and fact that such polymers are soluble in cresol makes them dried to yield a polymer of intrinsic viscosity of 0.58

advantageously useful as coating compositions for elecdL/gram and composed of recurring structural units of trical conductors whereby the conductor can be passed the formula 0| 0 H2CJJ\ i-CH:

NH-C-C H a H a H2C /'i JCH:

through the cresol solution of the polymer and the solvent where n is a whole number in excess of l. is driven off by heat and the polymer on the conductor core cured at elevated temperatures of the order of about EXAMPLE 5 ISO-300 C. for times ranging from 5 minutes to 1 hour. Employing the same procedure and equipment as de- The polymers obtained in this fashion are usually inscfflbhd m EXamPh? 4, 5 grams 11101) of the f sible d i 1 b1 oligomer of Example 3 (Formula VIII) was dissolved In addition to the use of heat alone, the acceleration 111 50 I111- Cfesol, 2 drops of tetramethylethylene diamifle of the polymers to the thermoset, i.e., the infusible and added a catalyst and hydfogfin Sulfide Passed Simiinsoluble state, can be accelerated by the employment of larly as 111 Example 4 at a temperature of about C- small amounts of organic peroxides or other free radical After Working P the p lym r in the Same manner as was producing agents normally used to accelerate polymerizadone in Example 4, a light, tan, resinous product was 9 obtained having an intrinsic viscosity of 0.25 dL/gram. Analysis of the polymer indicated that it was composed of recurring structural units of formula where n is a whole number greater than 1 as evidenced by the following analyses. Found (percent): C, 63.2; H, 4.23; N, 7.29; S, 7.50. Calculated (percent): C, 64.9; H, 4.20; N, 8.41; S, 6.41.

EXAMPLE 6 10 EXAMPLE 7 To a reaction vessel equipped with stirrer and thermometer were added 30 ml. cresol and 9.1295 grams (0.01 mol.) of the oligomer of Example 1 (Formula VI).

25 This mixture was warmed to about 60 C. to dissolve the oligomer and then the mixture was allowed to cool to around room temperature (about 27 C.) at which time 0.9419 gram (0.01 mol) ethanedithiol and 3 drops tri-nbutylamine were added. The mixture was allowed to stir 30 for about 2 /2 hours during which time the viscosity of the solution increased greatly. The polymer was isolated by pouring the viscous solution into methanol containing a small amount of acetic acid. The polymer which precipitated was then ground, washed with hot ethanol and 35 dried in a vacuum oven to yield 9.7 grams (96% theoretical) of a polymer having an intrinsic viscosity of 0.41

lowing analyses of the product indicated that it was composed of recurring structural units of the formula where n is a Whole number greater than 1. Found (percent): C, 68.1; H, 4.4; N, 8.7. Calculated (percent): C,

dL/gram and composed of recurring structural units of 68.21; H, 4.42; N, 8.84.

the formula i @N -o o-o s-on,oH,-s

H II (I; H

where n is a whole number in excess of 1.

Analysis of the polymer established that it was composed of the above units as evidenced by the following results. Found (percent): C, 67.9; H, 5.0; N, 8.1. Calculated (percent): C, 68.1; H, 4.41; N, 8.36. Although the polymer had a melting point above 300 C., it was soluble in dimethylformamide and films from this solvent could be cast quite readily to yield products which were tough and flexible.

EXAMPLE 8 Employing the same procedure and equipment as used in Example 7, 9.1295 grams (0.01 mol) of the oligomer of Example 1 (Formula VI), 30 ml. cresol, 2.0641 grams (0.01 mol), 1,10-decamethylene dithiol and 3 drops trin-butylamine were mixed together and allowed to react at ambient temperature for about 15 hours. The polymer which was obtained on precipitation when the reaction mixture was worked up similarly as in Example 7, was washed and dried to give 10.7 grams (95.67% theoretical) of a resin having a softening point of 220-230" C. and intrinsic viscosity of 0.34 dl./gram. A film of this polymer cast from dimethylformamide was found to be tough and flexible. Tests on this film established that the yield stress was 11,400 p.s.i.; ultimate strength 10,400 p.s.i.; and ultimate elongation 6.5%. This polymer was composed of recurring structural units similar to that of (XIII) H ll Formula XII with the exception that the terminal portion of the recurring unit SCH -CH S- was replaced by a terminal portion of the recurring unit of the formula z)1o The identity of this polymer was established by NMR and infrared spectroscopy and the following analyses. Found (percent): C, 69.8; H, 5.8; N, 7.9. Calculated (percent): C, 64.2; H, 4.14; N, 7.48.

EXAMPLE 9 Employing the same conditions and procedures as in Example 7, 2.1028 grams (0.01 mol) ethylene glycol dimercaptoacetate and 3 drops tri-n-butylamine were added to 9.0094 grams (0.01 mol) of the bisimide oligomer of Example 2 (Formula VH) dissolved in 25 ml. cresol. The mixture was allowed to stir at ambient temperature and after h hour the reaction mixture became highly viscous and was thereafter Worked up in the same manner as described in Example 7 to yield 10.1 grams (91% of theoretical) of a polymer having a softening point in the range of 212-242 C. Films cast from this polymer using dimethylformamide as a solvent showed a yield stress of 10,200 p.s.i.; ultimate strength 7,200 p.s.i.; and ultimate elongation 24%. This polymer which had an intrinsic viscosity of 0.30 dl./gram was identified in its structure by the following elemental analyses. Found (percent): C, 64.9; H, 4.8; N, 7.5. Calculated (percent): C, 64.2; H, 4.14; N, 7.48. This polymer was composed of recurring structural units as in Formula XI with the exception that the sulfur at the terminal end of each recurring unit was replaced by the unit Employing the same procedures and equipment as in Example 7, a polymeric composition was prepared whereby the oligomer described in Example 2 (Formula VII) was reacted with 2.0461 grams (0.01 mol) 1,10-decamethylenedithiol. The reaction was allowed to proceed for 45 minutes at ambient temperature after which the usual workup of the polymer was employed to give a resin in a yield of about 10.2 grams (93% theoretical) having an intrinsic viscosity of 0.32 dl./gram. Films cast from this polymer using dimethylformamide as the solvent had the following values: yield stress 11,000 p.s.i.; ultimate strength 9630 p.s.i.; ultimate elongation 36%. Analyses of the polymer showed that it was composed of recurring structural units similar to those of Formula XI in Example 6 with the exception that the terminal sulfur of the recurring unit was replaced by the --S(CH S radical. Following are the analyses of the polymer. Found (percent): C, 68.4; H, 5.7; N, 8.2. Calculated (percent): C, 65.11; H, 6.10; N, 8.76.

The polymers of Formula I can be treated by suitable means to form other polymers containing a sulfone linkage. Thus the polymer of Formula I can be dissolved in a suitable solvent, for instance, benzene, toluene, acetic acid, etc. and thereafter treated with an oxidizing agent employing a sufficient amount of the oxidizing agent to convert each sulfur in the recurring unit of Formula I to the sulfone (40 grouping. Such polymers will have the general formula 0 O .-l l .11. g H H A A H A x 11 where R and R, x and n have the meanings given above.

The oxidation reaction is generally conducted by heating the mixture of the polymer of Formula I with the oxidizing agent for a period of time and at a temperature (for example, from 1 to 5 hours at a temperature of from 50 to C.) until the desired polymer is obtained. The polymer can then be worked up and isolated in the same manner as was done in connection with the preparation and isolation of the other sulfur polymers of Formula I.

A typical example whereby a sulfone polymer of Formula XIII can be obtained is shown by the following.

About 5 grams of the polysulfide polymer of Formula X derived and prepared in accordance with Example 5 is placed in a reaction vessel equipped with a stirrer. Thereafter, 30 ml. glacial acetic acid is added and then 10 ml. of 30% hydrogen peroxide. The reaction mixture is stirred and heated at 60-65 for about 3 hours. The polymeric product which is obtained is removed by filtration and dried to give a polysulfone polymer composed of recurring structural units of the requisite formula where each sulfur is converted to the sulfone (-SO' group.

As pointed out previously the reaction between the oligomer and the sulfide may be carried out in an emulsion medium. Typically, such an emulsion medium will comprise the oligomer, advantageously a catalyst, a proton donor, a solvent (especially one which can also act as a proton donor), and a sufficient amount of water to make the emulsion sufliciently fluid to permit reaction between the oligomer and the sulfide and still allow the formed polymer to be readily dispersed in the emulsion as it is formed. Usual emulsifying agents, such as carboxymethyl hydroxyethyl cellulose, can be employed for forming the emulsion.

Polymers obtained by this emulsion method can be expected to have higher molecular weights and higher intrinsic viscosities. Problems concerned with the viscosity of the reaction medium are usually avoided since the polymer is in the form of suspended, very fine particles in a nonviscous medium. The polymer obtained The compositions of the present invention have appli- 5 cation in a wide variety of physical shapes and form, including the use as films, molding compounds, coatings, etc. When used as films or when made into molded products, these polymers, including laminated products prepared therefrom, not only possess good physical properties at room temperature but they retain their strength and excellent response to work-loading at elevated temperatures for long periods of time. Films formed from the polymeric compositions of this invention may be used in application where films have been used previously. Thus, the compositions of the present invention can be used in automobile and aviation applications for decorative and protective purposes, and as high temperature electrical insulation for motor slot liners, in transformers, as dielectric capacitors, as coil and cable wrappings (form wound coil insulation for motors), for containers and container linings, in laminating structures where films of the present composition or where solutions of the claimed compositions of, matter are applied to various heat-resistant or other type of materials such as asbestos, mica, glass fiber and the like and superposing the sheets one upon the other and thereafter subjecting them to elevated temperatures and pressures to effect flow and cure of the resinous binder to yield cohesive laminated structures. Films made from these compositions of matter can also serve in printed circuit applications.

Alternatively, solutions of the compositions herein described can be coated on electrical conductors such as copper, aluminum, etc., and thereafter the coated consilicones, polyvinylformal resins, epoxy resins, poly- 5 imides, polytetrafluoro-ethylene, etc. The use of the curable compositions of the present invention as overcoat on other types of insulation is not precluded.

Applications which recommend these resins include their use as binders for asbestos fibers, carbon fibers, and 55 other fibrous materials in making brake linings. In addition, molding compositions and molded articles may be formed from the polymeric compositions in this invention by incorporating such fillers as asbestos, glass fibers, talc, quartz, powder, wood flour, finely divided carbon, silica, into such compositions prior to molding. Shaped articles are formed under heat, or under heat and pressure in accordance with practices well known in the art. In addition, various heat-resistant pigments and dyes may be incorporated as well as various types of inhibitors depending on the application intended.

The compositions herein defined may suitably be incorporated in other materials to modify the properties of the latter or in turn their properties may be modified by the incorporation of the other material. For example, they may be compounded with substances such as natural or synthetic rubbers; synthetic resins such as phenol-aldehyde resins, urea-aldehyde resins, alkyd resins, etc.; cellulosic material such as paper, inorganic and organic esters of cellulose such as cellulose acetate, cellulose ether; such as methyl cellulose, ethyl cellulose, benzyl cellulose, etc. In some instances, plasticizers and other modifying agents may be used in combination therewith to yield products which when applied to a base member and air dried or baked have a high degree of heat-resistance due to the presence of the compositions herein defined.

It will of course be apparent to those skilled in the art that in addition to the compositions specifically referred to in the foregoing examples, other organic dithiols, oligomers, solvents, catalysts, proton donors, of Formula II, many examples of which have been described above, may be employed without departing from the scope of the invention. The processing techniques may be varied widely employing the many conditions recited previously.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A polymeric composition compound of recurring structural units of the formula Where the R is the same or different divalent organic radical selected from the class consisting of divalent hydrocarbon radicals of from 1 to 40 carbon atoms and divalent groups consisting of two aryl residues attached to each other through the medium of a member selected from the class consisting of an alkylene radical of from 1 to 10 carbon atom-s,

R' is a divalent alkylene radical of from 2 to 20 carbon atoms, x is 0 or 1, and n is a whole number in excess of 1. 2. A polymeric composition as in claim 1 wherein the recurring structural unit is 1 5 where n is a whole number in excess of l.

4. A polymeric composition as in claim 1 wherein the recurring structural unit is 5. A polymeric composition as in claim 1 wherein the 35 recurring structural unit is 3. A polymeric composition as in claim 1 wherein the recurring structural unit is where n is a whole number in excess of 1.

where n is a whole number in excess of 1.

OHJV JUNO OHJU JUNO w w w H H H N m LIL riiiiL where n is a whole number in excess of l.

6. A polymeric composition as in claim 1 wherein the recurring structural unit is 17 which process comprises elfecting reaction, in the presence of a proton donor, between a maleimide of the general formula with a sulfide selected from the class consisting of hydrogen sulfide and organic dithiols of the general formula where R is the same or difierent divalent organic radical selected from the class consisting of divalent hydrocarbon radicals of from 1 to 40 carbon atoms and divalent groups consisting of two aryl residues attached to each other through the medium of a member selected from the class consisting of an alkylene radical of (from 1 to carbon atoms,

boxylic acids, organic compounds containing weakly acidic hydrogen atoms in the form of nuclearly bonded hydroxyl groups, acidic inorganic salts and acidic organic salts.

8. The process as in claim 7 wherein the sulfide is hydrogen sulfide.

9. The process as in claim 7 wherein the sulfide is ethanedithiol.

10. The process as in claim 7 wherein the sulfide is ethylene glycol dimercaptoacetate.

11. The process as in claim 7 wherein the sulfide is 1,10- decamethylene dithiol.

References Cited UNITED STATES PATENTS 3,625,912 12/1971 Vincent et a1. 260-302 3,627,780 12/ 1971 Bonnard et al 260326.3 3,637,901 1/ 1972 Bargain et al 260830 3,669,930 6/1972 Asahara et al. 26047 WILLIAM H. SHORT, Primary Examiner L. L. LEE, Assistant Examiner US. Cl. X.R.

117-72, 126 AB, 128.4, 161 UN, 228; 161-197, 205, 227; 2604 R, 4 AR, 9 R, 17 R, 29.2 N, 29.6 HN, 30.2, 30.8 DS, 32.6 N, 33.4 P, 33.6 UA, 33.8 UA, 41 N, 47 CP, 63 N, 78 UA, 79, 326.3 824 EP, 841, 851, 857 UN, 873, 897 R 

